Self‐Healing Waterborne Polyurethane With Enhanced Mechanical Properties Based on Nano‐Silica

ABSTRACT Waterborne polyurethanes with self‐healing damage and restore mechanical properties became widely used. The self‐healing performance was closely related to good chain segment mobility, but loose chain segments could weaken mechanical properties. High mechanical performance and high self‐healing performance were contradictory. Therefore, research on how to ensure high self‐healing while improving the mechanical properties of materials became one of the research directions for self‐healing materials. In this work, waterborne polyurethanes with disulfide bonds were first prepared, and then nano‐silica was dispersed through mechanical stirring to obtain silica‐modified self‐healing waterborne polyurethane (SWPU‐SiX). The effect of nano‐silica content on the properties of SWPU‐SiX were studied. It was found that the tensile strength of the prepared material reached 16.58 MPa, and the toughness reached 67.51 MJ/m 3 representing increases of 397.57% and 150.43% compared to SWPU, respectively. It could be almost completely healed at 80C. The enhancement of these properties provides a new method for the research of self‐healing materials.